Paho MQTT C Client Library
Synchronous publication example
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "MQTTClient.h"
#define ADDRESS "tcp://"
#define CLIENTID "ExampleClientPub"
#define TOPIC "MQTT Examples"
#define PAYLOAD "Hello World!"
#define QOS 1
#define TIMEOUT 10000L
int main(int argc, char* argv[])
MQTTClient client;
int rc;
if ((rc = MQTTClient_create(&client, ADDRESS, CLIENTID,
printf("Failed to create client, return code %d\n", rc);
conn_opts.keepAliveInterval = 20;
conn_opts.cleansession = 1;
if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS)
printf("Failed to connect, return code %d\n", rc);
pubmsg.payload = PAYLOAD;
pubmsg.payloadlen = (int)strlen(PAYLOAD);
pubmsg.qos = QOS;
pubmsg.retained = 0;
if ((rc = MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token)) != MQTTCLIENT_SUCCESS)
printf("Failed to publish message, return code %d\n", rc);
printf("Waiting for up to %d seconds for publication of %s\n"
"on topic %s for client with ClientID: %s\n",
rc = MQTTClient_waitForCompletion(client, token, TIMEOUT);
printf("Message with delivery token %d delivered\n", token);
if ((rc = MQTTClient_disconnect(client, 10000)) != MQTTCLIENT_SUCCESS)
printf("Failed to disconnect, return code %d\n", rc);
return rc;
int MQTTClient_disconnect(MQTTClient handle, int timeout)
int MQTTClient_deliveryToken
Definition: MQTTClient.h:262
void * MQTTClient
Definition: MQTTClient.h:251
int MQTTClient_waitForCompletion(MQTTClient handle, MQTTClient_deliveryToken dt, unsigned long timeout)
int MQTTClient_create(MQTTClient *handle, const char *serverURI, const char *clientId, int persistence_type, void *persistence_context)
#define MQTTClient_message_initializer
Definition: MQTTClient.h:332
int MQTTClient_connect(MQTTClient handle, MQTTClient_connectOptions *options)
Definition: MQTTClient.h:132
int MQTTClient_publishMessage(MQTTClient handle, const char *topicName, MQTTClient_message *msg, MQTTClient_deliveryToken *dt)
void MQTTClient_destroy(MQTTClient *handle)
#define MQTTClient_connectOptions_initializer
Definition: MQTTClient.h:982
Definition: MQTTClientPersistence.h:74
Definition: MQTTClient.h:825
int cleansession
Definition: MQTTClient.h:870
int keepAliveInterval
Definition: MQTTClient.h:848
Definition: MQTTClient.h:272
int qos
Definition: MQTTClient.h:295
int retained
Definition: MQTTClient.h:314
void * payload
Definition: MQTTClient.h:281
int payloadlen
Definition: MQTTClient.h:279